Uranus is not the most distant planet, but it is the coldest.
Uranus is a planet in the outer solar system, as many students are aware. Neptune is the next known planet beyond its reach, and another huge planet may exist much further away (nicknamed "Planet Nine" by the astronomers who proposed its existence). Surprisingly for planetary scientists, it turns out that Uranus is the coldest planet in our solar system, not Neptune. This is due to Uranus's lack of an internal heat source to augment the heat of the sun.